Apparatus for molding articles



Dec. 29, 1942. E. LINDSTROM EI'AL I 0 ,9

APPARATUS FOR MOLDING ARTICLES Fi led Sept. 18, 1959 4 Sheets-Sheet 1INVENTOR ATTORNEYS Dec. 29, 1942. w. E. LINDSTROM ETAL 2,306,955

' APPARATUS FOR MOLDING Afi'ricLEs Filed Sept. 18, 1959 4. Sheets-Sheet3 1&2 121 114 64 M1 6??? fi hdsimm M ggi: 17B. fimg I ATTORNEYS- 1942-w. E. LINDSITROM E'II'AL 3 3 APPARATUS FOR MOLDING ARTICLES Filed Sept.18, 1959 Y 4 SheetsSheet 4 INVENTORS 71 MZ/redEZMds/mm 152 I PatentedDec. 29, 1942 UNITED STATES PATENT OFFICE APPARATUS FOR MOLDING ARTICLESWilfred E. Lindstrom, Oradell, and Gordon v. B. King, Convent, N. -J.,assignors to Lindstrom and King, West Caldwell, N. J., a partnershipcomposed of Wilfred E. Lindstrom and Gordon v.3. King ApplicationSeptember 18, 1939, Serial No. 295,426

as the amount of rubber, that amount of solvent 3 Claims.

This invention relates generally to the manufacture of formed or moldedarticles and has particular reference to improvements in apparatus formanufacturing such articles.

One object of the invention is to provide a simple durable mechanism formanufacturing articles from a plastic material at a high rateofreasonable limits.

With the foregoing and other objects in view the invention consists in anovel combination and relationof parts, one embodiment of which ishereinafter described with reference to the drawings accompanying andforming a part of this application, the novel features being pointed outin claims appended hereto.

, In said drawings:

Fig. 1 is a top plan view of an installation embodying the inventions.

Fig. 2 is an end view of the apparatus.

Fig. 3 is a horizontal section through the compression throat andmolding apparatus with the parts shown in an intermediate position.

Fig. i is a detail of the construction of the entering side of thecompression or extrusion throat.

Fig. 5 is a view, looking inthe opposite direction, of the constructionillustrated in Fig. 4.

Fig. 6 is a view along the line 6-6 of Fig. 1.

Fig. 7 is a view along the line 1-1 of Fig. 3.

91B- 8 is substantially the same as Fig. 3, the principal diflerencebeing that in Fig. 8 the parts are shown in the positions they occupywhen they have been moved to complete the molding and compression of oneof the articles.-

Fig. 9 is a view along the line 9-9 of Fig. 8.

The machine shown in the drawings is designed specifically for makingvalve packing rings used in steam and other valves and which can becompressed by adjustment of a gland nut or similar part to form a sealaround the valve stem. The material employed forthispurpose consists, byweight, of asbestos fiber about 60%, powdered graphite about 30%. andabout 1 of rubber or other suitable binder. These amounts can be variedwithin certain limits as great exactness is not required. The materialsmentioned are mixed and worked together with naptha or some othersolvent which readily evaporates, the

being sufllcient to produce a stiff plastic material which will maintainits shape after molding and compression until the solvent is evaporatedto leave the finished article.

The plastic material is supplied in cylinders 20 which may beinterchangeable so that a filled cylinder may be'readyto replace onewhich has beenemptied. The filled cylinder has sufiicient clearance atone end, as shown in Fig. 8, to engage over the rim 2| of an extrusionthroat construcapplied through the piston 22. After the cylinder 20 hasbeen set in position strong bolts or rods 24, only one pf which is shownin the drawings, are set to take up the strain exerted between a heavyblock 25 and a strong plate 26 back of the compression device 23. Whilethe device 23 is preferably a hydraulic jack, any suitable way ofapplying a heavy pressure to the plastic material may be employed.

The mechanism for molding and compressing the plastic material into thefinished article may be driven in any suitable way but in the drawings(Fig. 1) these parts are shown as being driven by an electric motor 21connected by a belt or chain 28 to a reduction or change, speed gear box29. The power transmitted through the gear box drives a shaft 32,preferably connected by memamount of solvent being about the same byweight bers 33 and 34 of any suitable construction to another shaft 35journaled in bearing members 36 and.3'l. Attached to the shaft 35 aretwo cams 38 and 39. The first mentioned of these cams is for drivingwhat is herein usually referred to as the mold slide or as the formingmold carrier and the second cam is for operating mech-.

anism which transfers the molded articles from the forming molds tocompression molds and then both compresses the articles in thecompression molds and ejects them therefromas hereinafter periphery ofthe cam 38. These rollers turn upon eccentrics carried by members 45(F'i 1) which can be turned and then fastened in position by the nuts40, thereby affording a means for accurately regulating the relation ofthe rolls with the cam to get exactness of movement of the slide or moldcarrier.

Integral with the-rectangular portion 4i of the slide operating memberis an arm or rod 41 hav ing a reduced portion 48, Figs. 3 and 8, pinnedor otherwise suitably connected to a member 49 forming a part of theconnections for operating the mold slide. The member 40 is looselypivoted upon a bolt 52 (Fig. 3) which is also used for anat the otherside to hold the molding members 53 firmly in position. Secured to theplate M is a block 51; although this may simply be a projection from theplate 5|. Fastened across the front of the block 51 is a plate 58. Thisplate is strongly fastened as at 50 (Fig. 8) to the block 51 and plate5| because it must take a tolerably heavy strain in the operationshereinafter described.

laid plastic will be forced within the mold mem-' Fastened in the. plate58 are two rode 0i and the plate. These rods serve as guides for members05 and 80 constituting movable parts of the forming molds and also serveas cores to give 1101-.

low centers to the molded articles.

The members 65 and 30 slide along the rods II and 02, the movement inone direction being limited by steps 01 adjustable in the plate 50, theinner ends of the stops cooperating with mem bers 09 integral with andforming flanges on the ends of the members 05 and 00.

The plate 5| and all of the parts carried thereby are limited to a closesliding movement by guides 1i and 12, Figs. 3, 8 and 9, bolted to framemembers 13 and 14 which are in turn secured to a frame member 15 forminga part of the stationary frame work of the apparatus.

The purpose of reciprocating the plate II is to bring the moldingmembers 53 alternately in alignment with the exit opening 10 of what isfor convenience referred to herein as the extrusion throat. That throatis made up of several members constructed and arranged to afford a readyinterchange of parts. The first of these parts is a member 11 having aninverted frustoconical interior. Mounted within the surface of themember 11 is a member 10 provided with curved wings or vanes 10 integralwith'the body a cylindrical or tubular interior 06. The rod 0| carriedby the vaned member 10 serves as a centering and forming core within thtubular portion to which reference has just been made. The member-05 isseated in a member 81 which is threaded intoa plate or bar attached tothe frame member 25. I

When the plate 5| has been shifted to the position in which it is shownin Fig. 8, the left hand mold member will be in alignment with thecylindrical portion 80 or the exit opening 16 from the extrusionmechanism and the distributed and her 53. As it is forced in it willcause the movable member to be driven along the rod BI until the movablemember is arrested by its stop 61.

-This insures afirm close filling of the interior of will seal off anyextrusion from the throat 10 un I til another mold member is brought inalignment with that throat.

Cooperating with each of the mold members 53 is a forming andcompression mold 9| or 53 held within' suitably shaped seats by clamps84 and bolts 55 at the sides of the plate 00, that plate, as previouslyindicated, beinga part of the stationary frame work of the mechanism.

Centered within the forming and compression molds 0| and 90 are rods 06and 01. held by flanges 88 and 00 and nuts I00 in the framing of themachine. Sl-idable on the rods 96 and 91 are members I03 and I04 closelyfitting the interiors of the mold members 0i and 93. Each of the membersI00 and I04 has reduced portions closely flttingwithin bars I05 and I00(Figs. 6 and 9) mold is moved endwise in the mold to transfer theformedarticle from the forming mold into the compression mold and, by afurther movement of the member 55 or 00, the material is compressedwithin the forming mold, this transfer and compression causing movementof the member III or I04 until arrested by the associated stop I00, themovable member 55 or 00 being forced into the interior of thecompression mold 05 or 00 is withdrawn from the compression mold of-themember 18. Extending through that body I is a rod 0| held in positioncentrally of the member .10 by a nut 82 drawing a flange 00 on II firmlyinto engagement-with the member. The

. purpose of the vanes 18 is to distribute or lay the material above theexit 10, therebycausing a better placement of the fibrous plastic thanif the vane construction was not used. Below the member 11 is anothermember 05 also having an inverted frusto-conicai interior which issubstantially a continuation of the interior of the member 11 to afforda further compression and laying of the plastic material. The conicalinterior of the member 85 terminates at its lower end in mentioned. Thatcam is surrounded by a rec'- tangular construction similar to theconstruction of the member 4I and acts through rollers III and III toreciprocate a plate II8 (Figs. 2 and '7) whichis constructed toprovidearms H4 and III constituting driving members for what is usuallyhereinafter referred to as the rocker arms. These rocker arms arethree-armed members H6 and H1, Figs. 3, 7, 8 and 9, pivoted upon theshaft 7 of a bolt H3 extending between top and botber H3 is reciprocatedby the cam 39 acting upon the rolls III and H2 the rocker arms H6 and HTare oscillated in unison around the center H3.

The other arms of the rocker arms H3 and H1 carry between them bolts orrods I2I and I22 and upon these bolts or rods are mounted connectionsfor actuating the members and 66 to transfer articles from the formingmolds 53 to the compression molds 9|, 93 and compress them; and themechanism for ejecting the compressed articles from the compressionmolds.

When the plate I and the forming molds have been shifted so as to alignone forming mold 53 with the extrusion throat I6, the other forming mold53 will be in alignment with the associated compression mold and rockerarms H6 are then actuated to drive the member 66, for example, into thecompression mold 93. This transfers the formed article from the formingmold into the rod I22 carried by the rockervarms and seated in lation ofthe rocker arms Band III. The mechanism for efiecting it is illustratedin the various figures, being particularly shown in Figs.

' 6 and 9, in both of which the parts associated with the left handcompression mo ld 9| appear in detail. As there illustrated, the rod orbolt I2I carries two links I32 and I33 extending rearward and passingthrough holes in the bar I05 previously mentioned. When the rocker armsH6 and III are swung through the intervening connections by the cam 39the bar I05 will be drawn toward the front of the machine carrying withit the member I03. Nuts I34 on the links I32 and I33 constitute a meansfor regulating the length-of the stroke of the member I03 when therocker arms are oscillated. The movement of the member -I03 issuflicient to drive the formed article out of the compression mold 9iinto a container or onto a conveyor (not shown) conveniently arranged topermit evaporation ofany solvent remaining in the article.

The apparatus has been described in considerable detail and it isthought to be clear that the slots in the top and bot-tom faces of aspacing f member I26 secured to the rod I22. Between the rocker arms-II6 and H1 and the arms I24 and I25 are springs I21 and I23 surroundingthe rod I22 and serving to hold the parts in proper relation on the rod.

The ends of the arms I24 and I25 are provided sociated compression mold,the rocker arms 'I I6 and,II'I will be swung to engage the shoulders I30with the flange 69 and force the compression member 66 into thecompression mold, thereby driving the formed material ahead of it andcomproduce throat and the other forming mold with the as pressing it inthe compression mold. As the arms I24 and I25 are driven into engagementwith the 'flange 69 by oscillating movement of the rocker arms H6 andH1, the arms will be separated slightly agains the tension of thesprings I21 and I28 as the rounded ends I29 pass over the flangep Afterthe compression is effected, the rocker arms H6, IIIv are then swung inthe opposite direction and shoulders I3I of the. arms I24, I25 willwithdraw the members 66 from the present embodiment is intended to fillthe forming molds 53 alternately and that the transfer of the formedarticle in one of the forming molds to the associated compression. moldis effected while the other forming mold is being filled-at thecompression throat I6. That is to say. the plate 5I and the formingmolds 53 are then shifted in' such a way that when a filled mold 53 isbrought into alignment with its compression mold the empty forming moldwill be aligned with the extrusion throat. As one of the forming moldsis brought opposite its compression mold the member or 66 is impelled bythe arms I24, I25 to transfer the formed article into the compressionmold and the material compressed in that mold. Thereafter the member I03or I04 as the case may be is operated as above indicated to eject thefinished article from the compression mold.

- From all of the foregoing it is obvious that the mechanism can bechanged by substitution of parts to manufacture articles of diflerentsizes and that the internal configuration of the forming and compressionmolds may be changed to articles of shapes other than the valve packingrings for which the specific apparatus shown and described is designed.It'is therefore notdesired to be limited to the disclosure of z thespecification and drawings except to the extent indicated in the claimswhich follow.

What is claimed is:

1. A machine for molding valve packing rings I throat to receive theextruded material and form compression mold in order to free the formingmold carrier plate 5I- for a shifting movement by the cam 38.

Withdrawal of the member 66 and shift of I the forming mold carrier 5|away from the compression mold 93"permits ejection of the, compressedarticle from the compression mold. This electing movement is alsoeffected by the oscilpartially pressed articles in the molds, a finalcompression mold for each preliminary mold, means for transferring themolded articles from the preliminary molds to the respective compressionmolds and furthercompressing the articles in the latter molds, means forelecting the compressed articles from the compression molds, and rodsmountedcentraily of the press throat, the preliminary molds and thefinal compression molds for forming and maintaining through thesuccessive operations the openings through the centers ofthe valvepacking rings.

2. An apparatus for molding valve packing rings comprising an extrusionpress for extruding a stifi plastic through a throat, preliminary moldsfor receiving the plastic from the press and each having a centrallydisposed rod, a slide carrying said preliminary molds movable topcsition said molds opposite the press throat and close said throat whenno mold is opposite said throat, final molds each having a centrallydisposed rod, means for ejecting the molded plastic from the preliminarymolds into the final molds while the rods in the preliminary and finalmolds are in axial alignment and finally compressing the plastic in thefinal molds and around the rods therein, and means for stripping theformed packing rings from the rods in the final molds and ejecting themfrom the final molds.

3. An apparatus for the purpose stated comprising an extrusion press forapplying heavy pressure to a stiff plastic'material and having a throatthrough which the material is expelled. a rod supported centrally 01'and extending to the mouth of the throat, a member slidable across themouth of the throat having unrecessed portions confining the plasticagainst the pressure 01' the press and preliminary mold cavities intowhich the plastic is eiectedand molded by the released pressure when oneoi said cavities is broughtinto alignment with the 'prus throat, a rodsupported centrally 0! each preliminary mold cavity, said rods being inaxial alignment with the rod in the press throat when the respectivepreliminary mold cavities are in alignment with the throat, membersslidable in one direction on the preliminary mold cavity rods by theplastic and stops thereiorto limit the amount of plastic formed in thepreliminary molds, final molds, rods supported centrally oi each of thefinal molds, and means for actuating the slidable 'Inembers first toslide the formed plastic-oi! of the rods in the preliminary molds and onthe rods in the final" molds and then into the compression molds tocompress the plastic in the final molds, and means for strippin thecompleted articles from the final mold rods and ejecting them irom saidfinal molds.

- WILFRED E. IINDSTROM.

GORDONv. B. KING.

